Meter lighting



Dees. 3, W40. A. N. cURTiss ET Al.l

METER LIGHTING Filed Deo. 3l, 1956 inn Gttorneg Patented Dec. 3, 1940 UNITED sTMEs PATENT orifice Vassos, New Canaan,

Conn., assignors to Radio Corporation of America,\a corporation of Dela- Ware Application December 31, 1936, Serial No. 118,430

2 Claims.

This invention relates to means for lighting the face-plate of meters and like indicating instruments.

indicating instruments have heretofore been constructed with one or more lamps arranged Within the meter casing, either behind a translucent face-plate or intermediate the cover glassv and the face-plate. Such mode of construction is objectionable,'not only because the close proximity of the lampfto the indicating mechanism may thermally or electrically aiect the operation of the device, but also because of the difficulties incident to lservicing the? lamps. The prior art is replete with lighting arrangements designed to obviate the above disadvantages. Thus, it has previously been proposed to mount the light source at a remote point behind a removable cap on the meter panel and to direct the light, as by a lens or series oflenses, either to the edge of the cover glass or to the surface of the face plate. Lens systems are, however, expensive, and usually require meter frames of special construction to hold the lamp and its lenses.

It has also been proposed to provide a lamp,

' and a reiiector therefor, positioned in front of the cover glass and supported 'on a bracket which protrudes outwardly from the panel holding the meter or other indicating device. Here the lamp is accessible, but if it is positioned at the top of the meter, light 'may be reiiected downwardly from the cover glass into the eyes of the observer, and if the lamp and its supports are positioned at the bottom 'of the meter, they may bar access to the Zero-setting screw or other adjusting device, with which most electric meters are provided. In any event, prior art lighting arrangements of this last described type present an unsightly appearance and constitute a sharp protuberance upon the meter panel which may catch the sleeve of the person operating the apparatus associated therewith.

The above and' other disadvantages inherent in prior art meter lighting arrangements are obviated in accordance with the present invention by the provision of a preferably arcuate or inverted U-shaped escutcheon in which the face plate oi the indicating device is framed, and having a lamp positioned between the open arms of the U, and a removable lid adapted to be snap-fitted thereover. The outer surface of this lid constitutes a continuation of the smooth outer surface of the escutcheon, which surface bulges outwardly adjacent the open ends of the U to receive and conceal a lamp. The lamp may be mounted upon the inner surface of the lid for removal (Cl. E40- 2.1)

therewith, or it may be supported on an arm spanning the otherwise open portion of the U, in which latter case the lamp is preferably supported in a horizontal plane with its leading end presented to the cover plate of the meter. In either case, the lamp is so positioned and arranged that when the lid is removed the zerosetting screw is readily accessible.

Certain details of construction, together with other objects and advantages, will be apparent and the invention itself will be best understood by reference to the following specification and to the accompanying drawing, wherein Figure l is a front elevation of a meter escutchcon with the `front face of a meter and pointer framed therein and having a lid or cover closed to conceal a lamp'for lighting the face of the meter,

Figure 2 is a iront elevation of the device of` Fig. 1 with the cover removed,

Figure 3 is a sectional view'taken on the line 3-3 of Fig. 1, and

Figure 4 is a sectional view of an alternative embodiment of the invention.

Referring now to the embodiment of the invention shown in Figs. l, 2 and 3, E designates' generally an escutcheon in which the front scale bearing surface III and pointery I2 of a meter M are framed. Escutcheon E includes a short cylindrical body portion I4 within which the case I6 of meter M is seated and an annular rim or frame I8 surrounding the outer end of the cylinder. One or more screws 20 are provided for removably securing the meter case It within the cylinder I4 and a screw' 22 projecting from the rear surface of lrim I8 receives a nut 24 for clamping the assembly to an oried panel P. A cover-glass 26 for the scale bearing face plate I0 of meter case I6 is secured within the escutchecn E, though, as will appear in connection with the embodiment of Fig. 4., it may alternatively be seated in the rim of the meter'casing itself.

`The mechanism Within casing I6 is of a type adapted to move thepointer I2 across .the scale It); thus, if lthe pointer is to indicate the quantity or intensity of an electric current, casing I5 may house a coil 28 mounted upon the same axle 3l) upon which pointer I2 is supported. Coil 28 will be understood to be mounted between the poles of an actuating magnet, not shown. Axle 39 preferably extends outwardly towards the face plate Ill and carries a coiled hair spring 32 which has its inner end xed to axle 3B and its outer end fixed to a member 34 pivoted on axle 30. Member 34 has a bifurcated portion 36 (Fig. 2) which nud extends downwardly from its pivot point 36 to receive the preferably flattened or eccentric end 40 of a screw 42 which extends through the cover glass 26 and is accessible, in a manner later described, from the front of the escutcheon E. Screw 42, bifurcated member 34 and hair spring 32 constitute elements of a mechanism, known in the art, for obtaining an initial or zerosetting of pointer |2 with respect to scale l0.

The escutcheon E may be made of insulating material, such as hard rubber, Bakelite or like plastic, or it may be made of a preferably nonmagnetic metal with the rim portion I8 either solid or hollow. Considered in outline, as Viewed from the front, the frame or rim portion i8 of the escutcheon is in the form of an inverted and rounded U with its outer surface preferably rising graduallyv as at 44 to form a protuberance 46 at each side of the recess 48 formed by the open terminal of the rounded arms of the U. The opposed parallel si-de edges of the portions 46 of the frame I8 are provided each with a narrow shoulder 50 (Fig. 2) for receiving a removable cover or lid 52, the outer surface of which constitutes a continuation of the surface of the protuberant portion 46 of the escutcheon E. The ends of this lid 52 or one of them may be bent inwardly, as at 54, to engage a complementary beveled edge 56 on the outer rim of the escutcheon. In tting lid 52 over recess 48 the inwardly bent end 54 first engages the beveled edge 56 on the escutcheon and with the side edges of the lid aligned with the narrow shoulders 50, it is pressed inwardly whereby it is snap-tted between the outstanding parallel side walls of the protuberance 46.

In the embodiment of the invention shown in Figs. 1, 2 and 3, there is a relatively thin, flat strip or arm 58 of insulating material forming part of the escutcheon beneath the cover 52. This arm 58 is provided with an orice 60 to receive the zero-setting screw 42 for the pointer mechanism, and a second orice 62 in which a removable socket 64 containing a` lamp 66 is seated. The orifice 62 in which socket 64 is seated preferably communicates with an orifice 68 in the cover glass 26 and the lamp 66 extends therein to present its rays to the body of the glass and to the face plate I of the indicating instrument. The lamp is preferably quite small and may be of the type known as a grain-of-wheat lamp.

The embodiment of the invention shown in cross-section in Fig. 4 may be similar in appearance, as viewed from the front, to that shown in Fig. 1. The removablevlid, designated |52 in Fig. 4, here constitutes a support for a bracket |64 which carries a lamp 66. A contact member for lamp |66 is carried by an insulating strip' its rays are projected upwardly and inwardly through the cover glass |26 to illuminate the pointer ||2 and scale bearing surface ||U.

The escutcheon of Fig. 4 is not provided with a cylindrical body portion for retaining the meter, as is the device of Figs. 1, 2 and 3, but is provided with a plurality of pins |`|6 disposed about its inner surface, which engage complementary pin holes in the rim of the meter casing 6. In this embodiment of the invention, the cover glass |26 is seated within the rim of the meter casing and the pointer adjusting screw |42, instead of passing through the glass, passes through the rim of the casing itself. The indicating mechanism within the casing ||6 is similar in all respects to that shown in Fig. 3.

Other embodiments of the invention will suggest themselves -to those skilled in the art. It is to be understood, therefore, that the foregoing description of typical embodiments of the improved meter lighting system of the invention is to be interpreted in an illustrative and not in a limiting sense except as required by the prior art and the spirit of the appended claims.

What is claimed is:

1. A device of the class described comprising an annulus adapted to frame the face plate of an indicating instrument, a portion of the inner periphery of said annulus spanning said face plate,

a recess in said annulus extending from the outer periphery to the inner periphery of that portion of said annulus which spans said face plate, a protuberance constituting a continuation of the outer surface of said annulus and terminating adjacent opposite side edges of said recess, means for mounting a lamp in said recess, a removable lid for concealing the contents of said recess, and means adjacent the said side edges within said recess for receiving said removable lid, said lid constituting a continuation of the said protruding portions of said annulus.

2. The combination with an indicating instrument comprising a case enclosing a scale-bearing surface, a pointer for said scale, a cover glass for said case and a member accessible from the front of said cover glass for obtaining an initial adjustment of said pointer with respect to said scale, of an annular escutcheon for said indicating instrument to which said insulating case is xed and in which said cover glass, scale and pointer are framed, a recess in escutcheon communicating with said adjusting member and extending from the outer to the inner periphery of said escutcheon, means to mount a lamp within said recess with lthe lamp presented to said cover glass for illuminating said scale and pointer, a removable lid for concealing said lamp and pointer adjusting member and adapted to be tted within said recess with its outer surface ush with the surface of said escutcheon, said lamp being so mounted with respect to said adjusting member that upon removal of said lid Asaid adjusting member is accessible.

ARTHUR N. CURTISS. JOHN VASSOS. 

